1. Field of the Invention
The present invention relates to a solar tracker that automatically adjusts an angle of a solar collector to enable the solar collector to effectively receive the sunlight while varying a position according to the angle of incidence of sunlight in a solar generator that converts solar energy into electrical energy, and more particularly, to a self-powered solar tracker capable of adjusting an angle of a solar collector using optical sensors, such that the solar collector can optimally receive sunlight, and also capable of tracking the sun using self-generating power.
2. Description of the Related Art
In general, a solar generator, consisting of solar cells, a storage battery, and an electricity conversion device, is a generator that collects sunlight using a solar collector panel having multiple solar cells installed thereon, and converts the solar energy into electrical energy. The solar generators varying in output capacity depending on the number of installed solar cells can generate as much amount of power as desired, at a desired place, allowing both large-scale and small-scale power generations, and thus the solar generators are increasingly used for a wide range of purposes, for home use up to large-scale industrial use.
The solar generators may be categorized into fixed type solar generators and sun-tracking type solar generators, according to the installation method of a solar collector panel.
The fixed-type solar generator has a structure in which a solar collector panel is fixedly disposed at a predefined angle at which the solar collector panel can receive the most amount of sunlight. This structure is simple and easy to install, and has a high durability and simple maintenance, whereas the amount of power generated varies drastically with the angle of incidence of sunlight, resulting in a low average efficiency of generation.
Meanwhile, the sun-tracking solar generators are classified into a single-axis tracker and a two-axis tracker: the single-axis tracker rotating a solar collector panel to track the sun from sunrise to sunset as the sun moves from the east to the west; and the two-axis tracker rotating a solar cell module to track the changes in a meridian altitude of the sun, wherein the single-axis tracker has a comparatively simple structure with less efficiency compared to the two-axis tracker, whereas the two-axis tracker has the solar cell module to be positioned always in a perpendicular direction to the incident direction of the sunlight, thereby being able to maximize the efficiency of generator.
To develop the aforementioned sun-tracking solar generators, technologies to collect solar heat or concentrate the sunlight by tracking the sun are required. Because the sun continuously changes in apparent position due to the rotation and revolution of the Earth, a solar tracker is required to effectively collect and concentrate more solar energy per a unit time.
A solar tracker may be categorized into two types of solar tracker: a coordinate calculating type in which a driving motor operates to track the sun according to coordinates calculated by a program; and an optical sensor type in which a driving motor is controlled to track the sun according to an output signal occasionally detected by optical sensors.
The coordinate calculating type has an advantage in tracking the sun, regardless of the weather conditions, but accumulated errors should be periodically corrected, and the difference in latitudes and longitudes that vary with regions hamper the maintenance and repair of the solar tracker. On the contrary, the optical sensor type has a comparatively simple structure, but cannot track the sun under the cloudy sky weather, and if such cloudy weather condition lasts for a long enough time for the sun to change in position, the solar tracker may not be able to track the sun since the sun may move beyond the range available for the solar tracker, so that operation consistency may not be achieved.
Further, the aforementioned conventional solar trackers of the coordinate calculation type and optical sensor type include a complex control board to run a program or to process optical sensing values. Accordingly, an additional power supply is required to run the control board and failures frequently occur due to a central processing unit (CPU) used in the control board.